JP2006250623A - Photodetection device and photodetection method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photodetection device and a photodetection method using an optical fiber probe applicable to a scanning probe microscope or the like. <P>SOLUTION: In this photodetection device 1, light from a light source 2 is condensed onto a sample surface Sa by an optical probe 10, and reflected and scattered light from the sample S is condensed onto the second focal position of an ellipsoidal mirror 3 by the ellipsoidal mirror 3 arranged so that the first focal position thereof agrees with the condensing position of the optical probe 10 on the sample surface Sa, and focused light from the ellipsoidal mirror 3 is transmitted selectively through an aperture 4a of an aperture plate 4 arranged coincidently with the second focal position of the ellipsoidal mirror 3, and transmitted light is detected by a photodetector 5. Hereby, the reflected and scattered light from the sample S can be detected without passage through the optical probe 10, and photodetection can be performed with a high S/N ratio regardless of the shape or optical characteristics of the sample surface Sa and the material or the thickness of a shielding coating film 13 of the optical probe 10, or the like. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a light detection device and a light detection method, and more particularly to a light detection device and a light detection method using an optical probe applicable to a scanning probe microscope or the like.

  In recent years, nano-order measurement and processing has been performed using SPM (scanning probe microscope) technology such as STM (scanning tunneling microscope) and AFM (scanning atomic force microscope). A near-field optical microscope that is capable of detecting optical characteristics in a minute region below the diffraction limit in this SPM is used as a measurement / evaluation apparatus in various fields such as biotechnology. . In addition, research and development of optical recording devices and microfabrication devices applying the above-mentioned near-field optical microscope technology is also in progress.

  In the near-field optical microscope, a fine structure having a size equal to or smaller than the diffraction limit is used as a probe, and near-field light is generated in the vicinity thereof by illuminating the probe tip. By scanning the probe on the sample surface in this state, the near-field light scattered by the electromagnetic interaction between the near-field light localized near the probe and the sample surface, or near-field light transmitted through the sample surface is detected. Thus, optical information (light intensity, spectrum, polarization, etc.) of the sample surface can be obtained.

  In the near-field optical microscope, generally, a core having a sharpened core projecting from one end of an optical fiber provided with a clad is provided around the core, and a metal such as Au or Ag is formed in the projecting part. An optical image having a resolution exceeding the wavelength of light can be obtained.

  When measuring the physical properties of a sample in a micro area using the near-field optical microscope, the shape of the sample is measured by detecting evanescent light localized in an area smaller than the wavelength of light on the sample surface. Then, the evanescent light generated by irradiating the sample with light under the total reflection condition is scattered by the optical probe and converted into scattered light. The near-field optical microscope guides this scattered light to the core of the optical fiber through the protruding portion where the optical probe is formed, and detects it with a detector connected to the other exit end of the optical fiber.

  That is, the near-field optical microscope can perform both scattering and detection by the optical probe.

  As described above, the near-field optical microscope can measure with high resolution, but there is a problem that the measurement range is as narrow as about several tens of um.

  Also, in recent years, in applications such as silicon wafer defect inspection, it is required to switch to high-resolution measurement using near-field light after measurement with low resolution, and to continue measurement and inspection of the same sample. .

  Therefore, conventionally, a defect inspection apparatus and a defect inspection method have been proposed in which an optical probe for detecting near-field light is incorporated into a normal optical microscope apparatus including an observation system using an objective lens, and a wide range measurement using propagation light is possible. (See Patent Document 1).

JP 2000-055818 A

  However, in the above prior art, the near-field light measurement (high resolution measurement) is performed after aligning the optical probe for near-field light detection with respect to the minute region desired to measure the physical properties specified by the wide range measurement by the objective lens. ) Is very difficult to align, takes a long time, and has poor usability.

  Therefore, the present invention realizes both a wide range measurement with a high S / N ratio using propagating light and a high resolution measurement using near-field light with a single condensing optical element, and reflection / reflection from the sample. Scattered light is detected without passing through a condensing optical element, and high S is obtained regardless of the shape, optical characteristics of the sample surface, and the material and film thickness of the light-shielding coating film of the condensing optical element such as an optical probe. An object of the present invention is to provide a photodetection device and a photodetection method for performing photodetection with an / N ratio.

  The light detection device according to claim 1 is a light source that emits light of a predetermined wavelength, a condensing optical element that condenses light from the light source on a sample surface, and a first focal position is the sample surface. An ellipsoidal mirror that is arranged to coincide with the condensing position of the concentrating optical element above and collects reflected / scattered light from the sample surface at a second focal position, and the ellipsoidal mirror Light selection means having an aperture that selectively transmits focused light focused at a bifocal position, light detection means for detecting transmitted light that passes through the aperture, and between the condensing optical element and the sample The above-mentioned object is achieved by providing moving means for relatively changing the distance.

  In this case, for example, as described in claim 2, in the light detection device, the condensing optical element may be an optical probe capable of emitting both propagation light and near-field light.

  For example, as described in claim 3, the light detection device includes a sample scanning unit that moves the sample in a scanning direction parallel to the sample surface with respect to the condensing optical element. Also good.

  Further, for example, as described in claim 4, the light detection device includes an element scanning unit that moves the condensing optical element with respect to the sample in a scanning direction parallel to the sample surface, and the element scanning. And an aperture scanning unit that moves the aperture in the scanning direction via the light selection unit according to the movement of the condensing optical element by the unit.

  For example, as described in claim 5, the light detection device may include wavelength control means for appropriately changing and controlling a predetermined wavelength emitted by the light source.

  According to a sixth aspect of the present invention, there is provided a light detection method in which light from a light source that emits light having a predetermined wavelength is condensed on a sample surface by a condensing optical element, and reflected / scattered light from the sample is The ellipsoidal surface is focused on the second focal position of the ellipsoidal mirror by an ellipsoidal mirror arranged so that the first focal position coincides with the condensing position of the condensing optical element on the sample surface. By selectively transmitting the focused light from the ellipsoidal mirror through the aperture of the light selection means arranged so as to coincide with the second focal position of the mirror, and detecting the transmitted light by the light detection means, The goal has been achieved.

  In this case, for example, as described in claim 7, in the light detection method, the condensing optical element may be an optical probe capable of emitting both propagating light and near-field light.

  Further, for example, as described in claim 8, the light detection method includes moving and scanning the sample in a direction parallel to the sample surface with respect to the condensing optical element, so that each position on the sample surface is measured. You may detect the reflected and scattered light from.

  Further, for example, as described in claim 9, in the light detection method, the condensing optical element is moved and scanned in a direction parallel to the sample surface, and the opening is opened via the light selection unit. Alternatively, the reflected and scattered light from each position on the sample surface may be detected by moving and scanning to the second focal position of the ellipsoidal mirror that fluctuates according to the movement of the condensing optical element.

  For example, as described in claim 10, the light detection method may appropriately change and control a predetermined wavelength emitted from the light source.

  According to the present invention, light from a light source that emits light of a predetermined wavelength is condensed on the surface of the sample by the condensing optical element, and the reflected / scattered light from the sample is at the first focal position. The light is condensed at the second focal position of the ellipsoidal mirror by the ellipsoidal mirror arranged so as to coincide with the condensing position of the condensing optical element on the sample surface, The condensing light from the ellipsoidal mirror is selectively transmitted through the apertures of the light selecting means arranged to coincide with each other, and the transmitted light is detected by the light detecting means. As a result, it is possible to realize both a wide-range measurement with a high S / N ratio using propagating light and a high-resolution measurement using near-field light, and passing reflected / scattered light from a sample through a condensing optical element. And can improve the usability The shape of the sample surface, the material of the light-shielding coating film of the light converging optical element, such as optical properties and the optical probe, regardless of the film thickness and the like, it is possible to perform light detection in high S / N ratio.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, since the Example described below is a suitable Example of this invention, various technically preferable restrictions are attached | subjected, However, The scope of the present invention limits this invention especially in the following description. As long as there is no description of the effect, it is not restricted to these aspects.

  1 to 5 are diagrams showing an embodiment of a light detection apparatus and a light detection method of the present invention, and FIG. 1 is a light detection to which one embodiment of the light detection apparatus and the light detection method of the present invention is applied. 2 is a schematic configuration diagram of a main part of the device 1. FIG.

  In FIG. 1, a photodetection device 1 is applied to, for example, a near-field optical microscope that measures optical properties in a minute region of a sample S, and condenses light emitted from the light source 2 and the light source 2. The optical probe (condensing optical element) 10 that irradiates the surface to be measured (sample surface) Sa of the sample S, the ellipsoidal mirror 3 that condenses the light reflected and scattered from the surface Sa to be measured, and the focused light selectively. And an aperture plate (light selection means) 4 in which an aperture 4a to be transmitted is formed, a photodetector (light detection means) 5 for detecting transmitted light, and the like.

  The light source 2 oscillates light based on drive power supplied from a power supply device (not shown), and the light wavelength conversion unit (wavelength control means) 6 switches the wavelength of light emitted from the light source 2. That is, the light wavelength conversion unit 6 switches the wavelength of the light emitted from the light source 2 when controlling the emission light wavelength according to the optical characteristics of the sample S.

  The light emitted from the light source 2 is incident on an optical fiber (not shown) through a collimator lens and a condenser lens (not shown), and an optical probe 10 is formed on the tip surface of the optical fiber.

  As shown in an enlarged view in FIG. 2, the optical probe 10 includes an optical waveguide portion 11 and a protruding portion 12, and the protruding portion 12 is covered with a light-shielding coating layer 13. The optical waveguide unit 11 is composed of an optical fiber in which a clad 15 is provided around a core 14, and the core 14 and the clad 15 are each formed of silicon dioxide-based glass. The structure of the clad 15 is controlled so that the refractive index of the clad 15 is lower than that of the core 14.

  The protruding portion 12 is formed of a conical core 14 protruding from the clad 15 at one end of the optical waveguide portion 11, and includes a first tapered portion (propagating light emitting portion) 16a and a second tapered portion (near-field light generating portion). 16b.

  The sample S is placed on a movement control unit (movement unit, sample scanning unit) 17, and the movement control unit 17 is configured by, for example, a three-axis actuator and the like, and the measurement surface Sa is placed on the optical probe 10. Then, the sample S is moved in the direction of approaching / separating, or the sample S is scanned in the scanning direction parallel to the surface Sa to be measured.

  When the light P emitted from the light source 2 (hereinafter referred to as propagating light P) propagates through the core 14 and reaches the optical probe 10, the light detection device 1 passes outside the optical probe 10 via the first tapered portion 16a. Is injected into. The surface of the first taper portion 16a of the optical probe 10 is formed in a conical taper shape, and an angle θ1 (hereinafter referred to as an inclination) between the normal line Ha of the surface of the first taper portion 16a and the optical axis Pa of the propagating light. The angle θ1) is less than the total reflection angle in the propagating light P and has a shape larger than 0 degrees.

  Therefore, most of the propagating light P incident on the optical probe 10 passes through the light-shielding coating layer 13 from the first taper portion 16a and is then emitted as refracted light to the outside of the optical probe 10.

  The light emitted from the optical probe 10 is collected at a position about several hundred nm to several um away from the tip of the optical probe 10 to form a light spot having high light intensity.

  The phenomenon that the light emitted to the outside from the optical probe 10 is collected at a position away from the tip of the optical probe 10 to form a light spot having a high light intensity is that the inclination angle θ1 is totally reflected in the propagation light P. It is an inherent phenomenon when it is less than a corner. In the conventional optical probe in which the inclination angle θ1 is formed to be equal to or greater than the total reflection angle as in the prior art, the light intensity is highest near the distal end of the optical probe, and the light intensity decreases rapidly as the distance from the distal end of the optical probe decreases. Only a light spot can be formed.

  The transition of the distance between the optical probe tip and the focused spot for each tilt angle of the optical probe 10 is as shown in FIG. 3, for example. FIG. 3 shows that when the refractive index of the first taper portion 16a is 1.53 and the emission medium is air, the incident angle is less than that at a total reflection angle of 40 °, and the optical probe 10 has a tip of several hundred nm to This indicates that light is collected at a position about several um away.

  The spot diameter can be controlled by the diameter D of the first taper portion 16a, the inclination angle θ1, and the wavelength of the propagation light P. Accordingly, the root diameter D, the inclination angle θ1, and the wavelength of the propagation light P of the first taper portion 16a are determined so as to have a spot diameter comparable to the required measurement resolution.

  In addition, although the 1st taper part 31a becomes a cone shape in FIG. 2, as shown in FIG. 4, the 1st taper part 16c which becomes a taper of a curved surface shape may be sufficient.

  As shown in FIG. 2, the second tapered portion 16b (near-field light generating portion) of the optical probe 10 includes a component in the vicinity of the fiber optical axis in the propagation light P propagating in the core 14, as shown in FIG. And the surface of the second taper portion 16b has a conical taper shape, and an angle θ2 (hereinafter referred to as an inclination angle θ2) formed by the normal Hb of the surface and the optical axis Pa of the propagating light P. Is a shape that is greater than or equal to the total reflection angle in propagating light P and less than 90 degrees.

  Therefore, most of the propagating light P incident on the optical probe 10 is reflected at the interface between the light-shielding coating layer 13 and the optical probe core 14. At this time, a part of the light P is reflected on the light-shielding coating layer 13. It exudes to the surface, propagates along the light-shielding coating layer 13 toward the tip of the optical probe 10, and becomes a surface plasmon localized at the tip. With this surface plasmon, a near-field light spot can be formed near the tip of the optical probe 10.

  The light-shielding coating layer 13 may be made of any material, but it is an Au thin film because the effect of enhancing near-field light by optical plasma is obtained and the chemical stability is excellent. Is desirable.

  The ellipsoidal mirror 3 is arranged so that the first focal point coincides with the position of the light spot collected at a position separated from the tip of the optical probe 10 by several hundred nm to several um, and the opening 4a has an elliptical shape. It is disposed at the second focal position of the surface mirror 3. That is, a confocal optical system in which the condensing point of the propagation light P emitted from the optical probe 10 and the opening 4a are conjugated is configured. Therefore, it is possible to perform measurement with high resolution also in the height direction of the measurement surface Sa of the sample S.

  In addition, by utilizing the fact that strong reflected / scattered light can be detected only when the measurement surface Sa of the sample S is at the focus position of the propagation light P emitted from the optical probe 10, the measurement surface Sa is measured at the focus position. It is also possible to obtain an image (contour image) sliced in a direction parallel to (optical sectioning).

  Then, a slice image is obtained for each constant increment in the height direction of the surface to be measured Sa, and a shape image of the surface to be measured Sa can be formed by superimposing by computer processing.

  The photodetector 5 is disposed in the vicinity of the opening 4a, receives only the component transmitted through the opening 4a out of the reflected / scattered light from the measurement surface Sa, photoelectrically converts it, and generates a luminance signal.

  The light detection device 1 creates an image based on the luminance signal generated by the light detector 5, displays the created image on a display unit (not shown), and the user displays the image displayed on the display unit. Based on this, the details of the measured surface Sa of the sample S can be measured and observed.

  Next, the operation of this embodiment will be described. First, the measurement operation of propagation light measurement (wide range measurement) by the light detection device 1 will be described.

  The light detection device 1 makes light emitted from the light source 2 enter an optical fiber (not shown) having an optical probe 10 formed at the tip thereof, enter the optical probe 10 through the optical fiber, and enter the optical probe 10. The emitted light is propagated through the core 14 as it is and emitted from the optical probe 10. The light emitted from the optical probe 10 is collected at a position away from the tip of the optical probe 10 to form a light spot.

  Here, the surface to be measured Sa of the sample S is moved in the direction of approaching and separating from the optical probe 10 by the movement control unit 17, and the surface to be measured Sa of the sample S is moved to the position of the light spot formed by the light collection. Match the position of. Information on the distance between the tip of the optical probe and the focused spot used at this time is obtained in advance by an experiment or the like.

  Next, the measurement surface Sa of the sample S is scanned in the horizontal direction with respect to the optical probe 10 by the movement control unit 17, and the light emitted from the optical probe 10 generated at that time is reflected from the measurement surface Sa. The scattered light is reflected by the ellipsoidal mirror 3 and condensed near the opening 4 a of the opening plate 4. In other words, the ellipsoidal mirror 3 is arranged such that the first focal position thereof coincides with the condensing position of the optical probe 10 on the measured surface Sa, and the reflected / scattered light from the measured surface Sa is transmitted to the second focal position. Is condensed at the position of the opening 4 a of the opening plate 4.

  Since the aperture 4a is disposed confocally in a conjugate relationship with the condensing point of the optical probe emission light, only the reflected scattered light from the condensing point in the optical probe emission light is selectively transmitted. The transmitted light transmitted through the opening 4a is received by the photodetector 5 disposed behind the pinhole, and the photodetector 5 photoelectrically converts only the component transmitted through the opening 4a to generate a luminance signal.

  The light detection device 1 creates an image based on the luminance signal generated by the light detector 5, displays the created image on a display unit (not shown), and the user displays the image displayed on the display unit. Based on this, the details of the measured surface Sa of the sample S can be measured and observed.

  In the measurement, the light detection device 1 selects the light wavelength in accordance with the dispersion characteristic of the light transmittance of the sample S by the light wavelength conversion unit 6 at the time of measurement. At this time, the light detection device 1 selects a wavelength having a high light reflectance. By doing so, the amount of detected light can be increased, and furthermore, light detection can be performed with a high S / N ratio.

  In addition, when the photodetector 1 uses a photodetector having a spectroscopic function as the photodetector 5 and oscillates light having a wide wavelength bandwidth in the light wavelength converter 6 and the light source 2, the light reflectance of the sample S is measured. Spectral information can be obtained.

  Further, the light detection device 1 detects the reflected scattered light generated from the measured surface Sa of the sample S with a high S / N ratio by using the ellipsoidal mirror 3 without using the light component returning to the optical probe 10. Can do.

  In addition, the photodetecting device 1 can perform high-resolution measurement by configuring a confocal optical system that also uses the aperture 4a.

  Furthermore, in the light detection device 1, the light reaching the opening 4a is only the light reflected and collected by the ellipsoidal mirror 3 among the reflected and scattered light generated from the surface Sa to be measured, and other light is transmitted. Since the light is blocked by the optical probe 10 and does not reach the opening 4a, the light condensed on the opening 4a becomes a ring-shaped light beam, and the condensed spot becomes minute. Therefore, by selecting an aperture diameter that matches the spot size as the aperture 4a, measurement with higher resolution can be performed.

  When the surface to be measured Sa of the sample S is scanned with respect to the optical probe 10 in the horizontal direction, if the height of the optical probe 10 with respect to the surface to be measured Sa is constant, control in the proximity / separation direction during measurement is unnecessary. Thus, coupled with the length of the distance between the tip of the optical probe and the focused spot (about several hundred nm to several um), scanning can be performed at higher speed, and the measurement time can be greatly shortened.

  Next, the measurement process of near-field light measurement (high resolution measurement) will be described. The light detection device 1 enters light emitted from the light source 2 into an optical fiber (not shown) having an optical probe 10 formed at the tip thereof, and enters the optical probe 10 through the optical fiber. The light incident on the optical probe 10 propagates through the core 14 as it is and enters the light-shielding coating layer 13 of the optical probe 10. At this time, near-field light as an evanescent wave exudes on the exit end side of the light-shielding coating layer 13.

  In the state in which near-field light is exuded, the light detection device 1 causes the movement control unit 17 to move the measurement target surface Sa of the sample S in a direction in which the measurement surface Sa approaches the optical probe 10. At this time, when the distance between the tip of the optical probe 10 and the measured surface Sa is equal to or less than ¼ of the wavelength λ of the light emitted from the light source 2, the near-field light oozed from the optical probe 10 is measured. The surface Sa is irradiated, and a minute light spot is formed on the surface Sa to be measured by near-field light.

  Of the near-field light that forms the light spot, the component that becomes scattered light on the surface Sa to be measured is condensed by the ellipsoidal mirror 3 and is transmitted through the opening 4a in the same manner as the detection method of the propagation light. High resolution measurement of the surface Sa to be measured Sa of the sample S can be performed by leading to the detector 5 and photoelectrically converting only the component transmitted through the opening 4a and generating a luminance signal.

  The light detection device 1 creates an image based on the luminance signal generated by the light detector 5, displays the created image on a display unit (not shown), and the user displays the image displayed on the display unit. Based on this, the details of the measured surface Sa of the sample S can be measured and observed.

  As a method for detecting near-field light, a method for detecting return light to the optical probe 10 without using the ellipsoidal mirror 3, that is, not shown through the core 14 through the light-shielding coating layer 13. A method for leading to a photodetector may be used.

  As described above, the light detection apparatus 1 according to the present embodiment condenses the light from the light source 2 on the sample surface Sa by the optical probe 10, and reflects / scatters the light from the sample S at the first focal position. The elliptical mirror 3 arranged so as to coincide with the focal position of the optical probe 10 on the sample surface Sa is condensed at the second focal position of the elliptical mirror 3, and the second focal position of the elliptical mirror 3 is The convergent light from the ellipsoidal mirror 3 is selectively transmitted through the aperture 4 a of the aperture plate 4 that is arranged so as to be detected, and the transmitted light is detected by the photodetector 5.

  Therefore, the reflected / scattered light from the sample S can be detected without passing through the optical probe 10, and the shape and optical characteristics of the sample surface Sa, the material of the light-shielding coating film 13 of the optical probe 10, the film thickness, etc. Regardless, light detection can be performed with a high S / N ratio.

  Further, the light detection apparatus 1 of the present embodiment uses an optical probe 10 that can emit both propagating light and near-field light as a condensing optical element.

  Therefore, it is possible to perform light detection at a high S / N ratio for both wide-range measurement using normal propagation light (propagation light measurement) and high-resolution measurement using near-field light measurement, and near-field light ( High resolution measurement can be performed.

  Furthermore, in the photodetector 1 of the present embodiment, the movement control unit 17 moves the sample S with respect to the optical probe 10 in the scanning direction parallel to the sample surface Sa.

  Therefore, high-speed measurement can be performed when the sample S is lightweight while improving the stability of the detection signal.

  Further, in the light detection device 1 of this embodiment, the predetermined wavelength emitted from the light source 2 is appropriately changed and controlled by the light wavelength conversion unit 6.

  Therefore, it is possible to select a wavelength with a high light reflectance of the sample S or oscillate a broadband light, and to appropriately increase the S / N of the detection signal and acquire the light reflection spectrum of the sample S. .

  In the above embodiment, the movement control unit 17 moves the measured surface Sa of the sample S in the direction of approaching and separating from the optical probe 10 and the scanning direction. The method of moving the relative position with the optical probe 10 is not limited to the above method. For example, as shown in FIG. 5, a probe control unit (element scanning means) 21 is connected to the optical probe 10, The probe control unit 21 scans the optical probe 10 in the scanning direction parallel to the measurement target surface Sa of the sample S to change the position of the light spot on the measurement target Sa, that is, the generation position of the reflected / scattered light. You may do it. Note that the probe control unit 21 may not only move the optical probe 10 in the scanning direction parallel to the surface to be measured Sa, but also move it in the direction of approaching and separating from the surface to be scanned Sa of the sample S. In this case, it is not necessary to use the movement control unit 17.

  On the other hand, an aperture scanning unit (aperture scanning means) 22 is connected to the aperture plate 4 in which the aperture 4a is formed, and the aperture scanning unit 22 moves the aperture plate 4, that is, the aperture 4a in the scanning direction. .

  That is, when the optical probe 10 is moved in a direction parallel to the surface to be measured Sa, light emitted from the optical probe 10 and scattered and reflected by the surface to be measured Sa enters the ellipsoidal mirror 3 to enter the ellipsoidal mirror 3. Since the position reflected and condensed at (the position in a conjugate relationship with the light spot) is also shifted, the aperture scanning unit 22 scans the aperture 4a by the amount of the shift, thereby enabling confocal detection.

  If the optical probe 10 is scanned without scanning the sample S in this way, even if the sample S has a large mass, or when the sample S itself is easily destroyed by operation, it is appropriate. Can be measured.

  Then, as described above, the light detection apparatus 1 moves the measurement surface Sa of the sample S in the direction of approaching and separating from the one optical probe 10, so that the light detection apparatus 1 uses the spot by the propagation light P or the near-field light. Spots can be selectively switched and formed on the surface Sa to be measured, and a single optical probe 10 can be used for wide S / N wide-range measurement using propagating light P and high resolution using near-field light. Both measurements can be realized.

  The invention made by the present inventor has been specifically described based on the preferred embodiments. However, the present invention is not limited to the above, and various modifications can be made without departing from the scope of the invention. Needless to say.

  It can be applied to a scanning probe microscope or the like used for nano-order measurement / processing.

BRIEF DESCRIPTION OF THE DRAWINGS The principal part schematic block diagram of the photon detection apparatus to which one Example of the photon detection apparatus and photodetection method of this invention is applied. The enlarged front view of the front-end | tip part of the optical probe of FIG. The figure which shows transition of the distance between optical probe front-end | tips and condensing spots for every inclination-angle of the optical probe of FIG. The enlarged front view of the example in which the 1st taper part of the optical probe of FIG. 2 is a curved taper. The principal part schematic block diagram of the photon detection apparatus in the case of moving an optical probe.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photodetector 2 Light source 3 Ellipsoidal mirror 4a Aperture 4 Aperture plate 5 Optical detector 6 Optical wavelength conversion part 10 Optical probe 11 Optical waveguide part 12 Protrusion part 13 Light-shielding coating layer 14 Core 15 Cladding 16a 1st taper part 16b 1st taper part 16b 2 taper part 16c 1st taper part 17 movement control part 21 probe control part 22 aperture scanning part

Claims (10)

  A light source that emits light of a predetermined wavelength, a condensing optical element that condenses the light from the light source on the sample surface, and a condensing position of the condensing optical element on the sample surface. And an ellipsoidal mirror that collects the reflected / scattered light from the sample surface at the second focal position and the focused light focused on the second focal position by the ellipsoidal mirror. A light selecting means having an opening to be transmitted through, a light detecting means for detecting transmitted light that is transmitted through the opening, a moving means for relatively changing the distance between the condensing optical element and the sample, A photodetection device comprising:   The optical detection device according to claim 1, wherein the condensing optical element is an optical probe capable of emitting both propagating light and near-field light.   3. The photodetecting device includes a sample scanning unit that moves the sample with respect to the condensing optical element in a scanning direction parallel to the sample surface. Light detection device.   The light detection device includes: an element scanning unit that moves the condensing optical element with respect to the sample in a scanning direction parallel to the sample surface; and the movement of the condensing optical element by the element scanning unit. The light detection apparatus according to claim 1, further comprising: an aperture scanning unit that moves the aperture in a scanning direction via the light selection unit.   The light detection apparatus according to claim 1, further comprising a wavelength control unit that appropriately changes and controls a predetermined wavelength emitted from the light source.   Light from a light source that emits light of a predetermined wavelength is condensed on the sample surface by a condensing optical element, and reflected / scattered light from the sample is collected at the first focal point on the sample surface. The elliptical mirror arranged so as to coincide with the condensing position of the optical element for light is condensed at the second focal position of the elliptical mirror, and is arranged so as to coincide with the second focal position of the elliptical mirror. A light detection method comprising: selectively passing the focused light from the ellipsoidal mirror through the opening of the light selection means, and detecting the transmitted light by the light detection means.   7. The light detection method according to claim 6, wherein the light collecting optical element is an optical probe capable of emitting both propagating light and near-field light.   The light detection method is characterized by detecting the reflected / scattered light from each position on the sample surface by moving and scanning the sample in a direction parallel to the sample surface with respect to the condensing optical element. The photodetection method according to claim 6 or 7.   In the light detection method, the condensing optical element is moved and scanned in a direction parallel to the sample surface, and the aperture is changed according to the movement of the condensing optical element via the light selection means. The light detection method according to claim 6, wherein the second focal position of the ellipsoidal mirror is moved and scanned to detect reflected / scattered light from each position on the sample surface. The light detection method according to any one of claims 6 to 9, wherein the light detection method appropriately changes and controls a predetermined wavelength emitted from the light source.

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